Switched-mode circuits, including switched-mode power supplies and motor controllers, are pervasive in many electronic applications from computers to automobiles. Generally, voltages within a switched-mode power supply system are generated by performing a DC-DC, DC-AC, and/or AC-DC conversion by operating a switch coupled to an inductor or a transformer. Switched-mode power supplies are usually more efficient than other types of power conversion systems because power conversion is performed by controlled charging and discharging a low loss component, such as an inductor or transformer, thereby reducing energy lost due to power dissipation across resistive voltage drops. Similarly, switched-mode motor controllers may be used to efficiently commutate DC brushless motors with low losses in the driving circuitry.
With respect to implementing a switched-mode circuit, specialized driving circuitry is used to efficiently drive a switching transistor coupled to the various magnetic components. Such circuitry may be configured to provide switching signals at appropriate speeds and voltage levels. These voltage levels may be established, for example, by using external DC supply voltages, voltage regulators, level shifters, charge pumps and other circuits to ensure that the switching transistor is turned-on and off. Each time the driving circuitry drives the switching transistor through one switching cycle, power may be consumed due to the charging and discharging of the input capacitance of the switching transistor.